Process for tanning or impregnating hides.



KURT r-razani onnnnsrnrm, nnssn imssau, GEBMANY,'ASSIGNOR r0 THE CORPO- 'RATION. or ,ANI-IYDAT-LEDER-WERKE AKTIENG-ESELLSCHAFT, or .HERSFELD,

sp ifi i mete tent. Patented Nov. '19; 1918.

. GERMANY. I

3' PROCESS "FOR TANNING 0R IWIPBEGBTATING IiIDES.

No Drawing.

: TozaZZ whom itymayiconcern:

Be it known that .LlinnrzHanmmcitizen of the GermanLEmire,rand. resident of I-Iersfeld,: HesseeNassau,Germany, with the Supost-xoifice address .Hainstrasse =14, haverinvented newxand useful *Improvements in Processes for Tanning or Impregnating Hides, of which the following is a specificavaluablewhen :used :in' connectionrwith the tion.

My invention relates to improvements in tanning or impregnatingfi hidesmby means of viscous substances, especiallyibituminous substances as for lnstance natural or art1fi-.

sembling leather, issued to Werner Spaltement with liquids that have an attraction for Water as for instance alcohol, acetone or their homologues.

I have found that it is impossible to impregnate hides with substances of a strong viscous nature by merely placing them in a molten mass.

Although it seems to be obvious, to raise the liquidity of the molten mass by raising the temperature, this could not be done as temperatures, that exceed 95100 G. are injurious to animal hides.

For this reason it was necessary to make use of the so called difiusion process, which consists in filling thehides first with a solution and then treating the same by a molten mass, the latter being soluble in the solvent used before.

Now it has been found, that this procedure may be dispensed with by the process, which forms the subject of the present application.

According to my invention the hides are dehydrated andwhen completely dry placed into a closed receptacle. The air in this receptacle is then evacuated and the molten mass is introduced while a high vacuum is maintained continuously. As soon as the myself. 1

holz and myself, that is to say by a treat- Applicationfiled February 16, 1916. .Serial lilo. 78,581.

.hides are completely covered by the :molten mass, the vacuum is stopped .it is preferred It); has beenfound, that. by this unanner the'liquid will; easily penetrate'into. the pores ofrthehides vand fill them completely.

r The zpresent invention is .salso :espeicially process described *in Unitedv StateslPatent 4N0: 1300,1416-datedflctober 3;l9l6gifor the Imanufacture of leather products :resembiting leather, issued to l/Verner Spalteholz and When hides are impregnated according to said process, the molten mass becomes enriched with benzene, or other liquid solvent as the case may be after each impregnation. This benzene or other liquid solvent must be expelled from the molten mass by distillation with water vapors. However it is unavoidable, that after the distillation more or less water will remain in the molten mass; this water however is ofvery injurious influence to the hides in somecases.

If on the contrary the hides, which are previously wholly dehydrated by a treatment with alcohol, acetone or their homologues, are impregnated with the molten mass by means of a vacuum and under following pressure, a reliable and complete impregnation is obtained. This is due to the known fact, that the previous dehydration makes the hides considerably more resistant against elevated temperatures.

It is to be remarked, that'without special precaution it is not possible to impregnate hides with this molten mass under pressure, as it would be necessary to use temperatures, that would injure the hides under normal conditions.

Therefore the new process does not only present the peculiar advantages of the known use of a vacuum in similar cases, but it allows in the first instance to dispense with the use of benzene and all other inflammable substances; besides the distillation with water vapors for'the elimination of the benzene is dispensed with and thereby the danger of injuring the hides by the remaining water is removed.

When I speak of alcohols I mean also to inclndeketones and when I speak of hide I mean to include both hide and skin in the untanned state and leather.

Now what I claim and desire to secure by Letters Patent is the following:

1. The art of tanning hides comprising reducing the atmospheric pressure on the hides and then treating the hides While under reduced pressure with a molten asphalt-i0 material, substantially as described.

2..Tl1e art of tanning hides comprising reducing the atmospheric pressure on the hides, treating the hides While under the reduced pressure with a molten asphaltic material and then subjecting said hides to a pressure exceeding atmospheric pressure.

8.The art of tanning hides comprising dehydrating hides by means of a substance having an attraction for Water and impregnating the hides with filling substances While under a reducedpressure.

4. Theart of tanning hides comprising dehydrating the hides by means of a suitable substance having an attraction for Water and impregnating the hides with a molten as-' phaltic material under reduced pressure.

5. The art of tanning hides comprising dehydrating the hides by means of an alco- That I claim the foregoing as my invention, I have signed my name in presence of two Witnesses, this 26th day of January, 1916. 7

near HARIEG.

Witnesses dean Game, 6 GRUND.

copies of. thispatent may be obtained for five cents each, by addressing the Goinmissioneroi Patents,

Washington, t3. 

